Network Bandwidth
Network Bandwidth
Objectivity/DB moves fixed size pages (blocks) of data between the client cache and local or remote files. The database application sets the page size for a database or container when a new file is created. It is typically 8 KB or 16 KB on modern file systems, corresponding to the unit of transfer between the operating system and disks, but it can range from 512 bytes to 64 KB. Clearly, a low bandwidth (e.g. 2400 Baud)communications line between the client and a data server would be a prohibitive bottleneck. Objectivity recommends at least 100 Mbit Ethernet connectivity.
The network bandwidth should be high enough to support the peak traffic between all clients and remote data sources. If this is impossible then the clients should use regular messaging protocols (CORBA, RMI etc.) to communicate with application or query servers that are more tightly coupled to the data storage devices. This will reduce the traffic requirements on the lower bandwidth lines.
An alternative technique is to periodically replicate subsets of the federation to the “remote” sites so that the majority of the data requirements of the clients at the end of low bandwidth lines can be satisfied locally.
